When building a jar file with maven, it will create a manifest file in META-INF/MANIFEST.MF. Its contents currently are:
Manifest-Version: 1.0
Add
false
to configration section of maven-jar-plugin in your pom.xml to completely remove default properties:
org.apache.maven.plugins maven-jar-plugin false
to customize it (remove just username):
org.apache.maven.plugins maven-jar-plugin